In recent years, devices such as digital VTRs and DVD players which process digital moving image signals have widely spread. Along with the advance of AV devices and computer devices, editing of moving images is becoming popular not only in studios but also at home. In some systems developed for editing of moving images, playback description data called a play list is created to switch between a plurality of moving images, or video effect processing is executed in real time during playback to largely shorten the time for moving image editing. As such a movie format, QuickTime available from Apple is known. QuickTime can handle a plurality of video and audio tracks. It can also set a video transition effect between tracks.
FIG. 15 is a view of track images when a transition effect of wipe is set for a multi-track play list as a real time effect in the playback mode.
MovieA.mpg is set from 0 to 4 sec in Video Track-1. MovieB.mpg is set from 3 to 7 sec in Video Track-2. The playback designation time of Video Track-2 leads the end time of Video Track-1 by 1 sec. This is because the transition effect by wipe is produced at this 1-sec overlap between Video Track-1 and Video Track-2.
Effect Track is data to control effect application to the two tracks. In this example, Effect Track is divided into three blocks. From 1 to 3 sec, Video Track-1 is played back without any effect. From 3 to 4 sec, the transition effect is applied between Video Track-1 and Video Track-2. From 4 to 7 sec, Video Track-2 is played back without any effect.
FIGS. 16A and 16B show the data tree structure of this play list.
Referring to FIG. 16A, reference numeral 300 denotes an overall play list; and 100, management information. The management information contains tracks 110, 120, and 140 which have track IDs 111, 121, and 141 and play list data 113, 123′, and 143′, respectively. Contents 115, 125, and 145 in the tracks have reference tables 116 and 126 as reference information to the actual movie take files or reference information 146 to the effect description file, and pieces of content data information 117, 127, and 147, respectively. The pieces of content data information contain content management data 118, 128, and 148″ containing detailed information of the contents, and block management data 119, 129, and 149′ which manage the playback times of data blocks in the contents.
Referring to FIG. 16B, an effect description file 200 contains processing description blocks 201, 202, and 203.
FIGS. 17A to 17D show the actual data structure of the play list.
FIG. 17A shows examples of the reference tables 116, 126, and 146 shown in FIG. 16A. MovieA.mpg is described in the reference table 116 of Video Track-1. MovieB.mpg is described in the reference table 126 of Video Track-2. An effect description file Effect.dcr is described in the reference table 146 of Effect Track.
FIG. 17B shows examples of the play list data 113, 123′, and 143′ shown in FIG. 16A. In Video Track-1, playback of 4 sec from the start is set. In Video Track-2, playback of 4 sec from the start is set after a blank of 3 sec. In Effect Track, playback of 7 sec from the start is set. With this setting, play list payback of 7 sec in total described with reference to FIG. 15 is done.
FIG. 17C shows examples of the content management data 118, 128, and 148″ shown in FIG. 16A. In the content management data 118 of Video Track-1, A-1 is set as the content ID, and Mpeg2 movie is set as the content. In the content management data 128 of Video Track-2, B-1 is set as the content ID, and Mpeg2 movie is set as the content. In the content management data 148″ of Effect Track, E-1 and E-2 are set as the content IDs.
E-1 indicates the Effect Track content corresponding to the no-effect portions of 0 to 3 sec and 4 to 7 sec described with reference to FIG. 15. Effect_Off is set as a flag for effect control. E-2 indicates the Effect Track content corresponding to the portion of 3 to 4 sec in FIG. 15. Effect_On is set for real-time effect processing.
FIG. 17D shows examples of the block management data 119, 129, and 149′ shown in FIG. 16A. In the block management data 119 of Video Track-1, a playback time table of data blocks 1 to 8 is set in correspondence with the content with the ID A-1. In the block management data 129 of Video Track-2, a playback time table of data blocks 1 to 8 is set in correspondence with the content with the ID B-1. For Effect Track, a playback time table of data blocks 1 and 3 is set in correspondence with the content with the ID E-1, and a playback time table of data block 2 is set in correspondence with the content with the ID E-2. This description indicates that, in FIG. 15, each of MovieA.mpg and MovieB.mpg contains eight blocks of 0.5 sec each, and Effect.dcr contains two data blocks of 0.5 sec each, which should sequentially be played back.
FIG. 18 shows an example of the effect description file 200. In block 1 of data blocks 1 to 3 of Effect Track, the effect type is No Effect, and the source is Video Track-1. In block 2, the effect type is Wipe, and Video Track-1 and Video Track-2 are set as the source. That is, the type of real-time effect is designated. In block 3, the effect type is No Effect, and the source is Video Track-2.
Such a video effect in playback requires a high player function. Especially, it is difficult to execute effect processing while playing back a plurality of video tracks, as in the transition effect. Japanese Patent Laid-Open No. 2002-218385 proposes a description method, in which a moving image file prepared by rendering only the effect portion in advance is inserted during playback in a playback description language such as SMIL. With this method, playback with an advanced effect can be executed even by a player with a low processing power.
However, the technique disclosed in Japanese Patent Laid-Open No. 2002-218385 is implemented on the basis of a data structure mainly composed of a single video track. This invention can hardly directly be applied to a moving image format such as QuickTime which has a plurality of video tracks.